Structure an aircraft rotor blade

ABSTRACT

An aircraft rotor blade structure is disclosed. The rotor blade includes a read blade part made of a pearl board and a front blade part made of a plastic material. The front blade part is connected to the front edge of the read blade part. This read blade part helps reducing the weight of the blade. The front blade part enhances the transverse strength of the read blade part and renders a center of gravity on the front edge of the blade.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to the structure of an aircraft rotor blade and,in particular, to a rotor blade made of lighter materials and easy tocontrol its center of gravity during its assembly.

2. Related Art

A rotorcraft gains an uplifting force from the rotation of its rotor.Its tail rotor cancels the torque produced by the rotating rotor, sothat the aircraft can fly stably in the air. It is thus seen that thedesign of rotor blades is a key factor that control the flying stabilitythereof.

To achieve a better balance state of the rotor blades, the blades ofmany model helicopters are designed to have a center of gravity towardits front edge. The conventional blade is made of wood and thus heavier.Its center of gravity is also difficult to control. When a helicopterbreaks one of its blades, the wooden blade may hurt observers.Alternatively, there are also blades made purely of pearl boards.However, they have a weaker strength. In that case, it is harder tocontrol the flight of the helicopter.

As shown in FIG. 3, the conventional rotor blade 9 of the rotorcraft ismade of a compound wood. In practice, the rear part of the blade 9 hasto be drilled and a heavy object has to be disposed in a recess in thefront part, so that the center of gravity of the blade can fall near itsfront edge. However, such a blade has a higher cost because it uses acompound material, followed by machining and weight adjustment. Theposition of the drilled hole and the weight have to be carefullycalculated. Any mistake may easily result in imbalance of the blade. Asin the case of wooden blades, the blades made of pearl boards also havethe same danger when they break.

In summary, it is useful to provide a blade that is easy to manufactureand adjust its center of gravity toward its front edge. Moreover, it ishighly desirable for the blade of have lighter weight and tensilestrength for flight.

SUMMARY OF THE INVENTION

An objective of the invention is to provide a rotor blade for anaircraft. The rear part of the blade is made of the lighter pearl board.Its front part uses a plastic material to increase the strength of therear part and to move the center of gravity forward. Therefore, theentire blade is light and easy to control the position of its center ofgravity. Not only can the invention enable the aircraft to achievecertain stability, the assembly cost is also lower. Moreover, thedisclosed blade causes less damage when it breaks.

In accord with the objective, the disclosed rotor blade includes:

-   -   a rear blade part in the rear part of the blade and made of a        pearl board;    -   a front blade part in the front part of the blade, made of a        plastic material, and connected to the front edge of the rear        blade part; and    -   a through hole for the blade to connect to the rotor.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will become more fully understood from the detaileddescription given herein below illustration only, and thus is notlimitative of the present invention, and wherein:

FIG. 1 is a three-dimensional assembly view of the invention;

FIG. 2 is a three-dimensional exploded view of the invention; and

FIG. 3 is a three-dimensional structural view of the rotor blade in theprior art.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be apparent from the following detaileddescription, which proceeds with reference to the accompanying drawings,wherein the same references relate to the same elements.

FIGS. 1 and 2 show an embodiment of the invention. The invention,however, is not limited to this particular example.

According to the embodiment, the disclosed rotor blade includes a rearblade part 1 in the rear part of the blade and a front blade part 2 inthe front part of the blade.

The rear blade part 1 is made of a pearl board. Its one end has an arcnotch 11. One side of the arc notch 11 is formed with a recess part 12.

The front blade part 2 is made of a plastic material. It is formed witha through hole 21 in the part corresponding to the arc notch for theblade to connect to the rotor (not shown). The front blade part 2 isconnected to the front edge of the rear blade part 1 by thermalcompression bonding. After the front blade part 2 and the rear bladepart 1 are connected, the through hole 21 of the front blade part 2coincides with the recess part 12 of the rear blade part 1.

Since the rear blade part 1 is made of the pearl board and the its frontedge is connected to the front blade part 2 by thermal compressionbonding, the center of gravity of the blade thus falls at the front edgeof the blade. The front blade part 2 made of the plastic materialstrengthens the soft pearl board and thus the entire blade. Thedistortion on both ends of the blade during the flight can be reduced.Therefore, the aircraft is less likely to encounter flight instabilitydue to an insufficient uplifting force.

Although the invention has been described with reference to specificembodiments, this description is not meant to be construed in a limitingsense. Various modifications of the disclosed embodiments, as well asalternative embodiments, will be apparent to persons skilled in the art.It is, therefore, contemplated that the appended claims will cover allmodifications that fall within the true scope of the invention.

1. An aircraft rotor blade, comprising: a rear blade part in the rearpart of the blade and made of a pearl board; a front blade part in thefront part of the blade, made of a plastic material, and connected tothe front edge of the rear blade part; and a through hole on the frontblade part for the blade to connect to the rotor.